1. Technical Field
The present invention relates to an electronic apparatus, a moisture-proof structure of an electronic apparatus, and a method for producing an electronic apparatus.
2. Related Art
In recent years, a display device having a flat, flexible, compact, and lightweight body has attracted the attention of the industry as an effective means for reducing the thickness of an electronic apparatus and enhancing portability thereof. A plastic substrate is used as the substrate of such a display device and an electronic apparatus that is provided with such a display device. The plastic substrate has a disadvantage in that it does not prevent moisture. As a typical problem recognized in the related art, since the plastic substrate does not exclude moisture, the display element(s) of a display device could degrade due to any vapor/moisture that permeates the substrate, resulting in a shortened service life thereof.
One possible technical solution to such a problem is to seal the display element of a display device by means of a pair of moisture-proof films. Specifically, one of the pair of damp-proof films is adhered to the other thereof at the (outer) edges of the display device in such a manner that the pair of damp-proof films envelopes the entire body of the display device for protection against moisture. One example of such a sealing method is disclosed in JP-A-10-133604. In the configuration of some electronic apparatuses, for example, card-type electronic apparatuses, display element is provided on a substrate so as to constitute a single integrated body that is made up of a display device and an electronic apparatus. When the above-described sealing method that is disclosed in, for example, JP-A-10-133604 is applied to this type of an electronic apparatus, it is difficult to adhere one of the pair of damp-proof films to the other thereof at the peripheral region around the display element. Therefore, when the sealing method of the related art is applied to such a type of electronic apparatus, the moisture-proof film is adhered to the surface of the plastic substrate of the electronic apparatus at the peripheral region around the display element thereof.
Generally speaking, in comparison with a case where two moisture-proof films are adhered to each other, the strength of adhesion is relatively small when a moisture-proof film is adhered to a plastic substrate by means of an adhesive because the adhesive property of the plastic substrate is insufficient. For this reason, in the above-identified sealing method of the related art in which the moisture-proof film is adhered to the surface of the plastic substrate of the electronic apparatus at the peripheral region around the display element thereof, it is practically impossible, or at best difficult, to prevent moisture/vapor from permeating through a weak adhesion region where the moisture-proof film is adhered to the surface of the plastic substrate over a long period of time.